What type of personality traits, habits, topics of converstaion or other information should i know about goths? (psychology)

They tend to revolve more around themselves than other people. Not in a negative, center of the universe way. But more of a they prefer to stay out of the way and be themselves kind of way.
They tend to go with what I always thought was a perfect slice of punk and trend. They don't all follow modern trends, but they still do what other punks and gothic people consider "trendy" or "cool".
I'd also like to point out that Thrashards, punks, rockers, and metalheads exist in a different spectrum. Thrashards and punks listen to a thrashier, more hardcore, and "skate punk" as it's called, kind of sound. Rockers and Metalhead's culture derives solely from the music. 
Gothic, emo, and anti-society trend is all about being unique and standing out. But this can result in a lot of backlash. This is why Gothic and Emo culture usually seems so depressed.

I hope this helps! :)